Good to see you're still writing, after the reception
"Tortured Echo" received.  The only way to get better
is to keep writing.  (You may want to continue in the
shortfic vein for a while; it's easier to improve
rapidly.)

He retrieved his sleeping 
back from his backpack and curled up in it.

During the night, the temperature dropped considerably, but 
Ryoga slept and did not know this. Nor was he aware of the 
blizzard which hit so suddenly and so devestatingly, covering 
the ground in a thick blanket of snow which was easily knee-deep 
to a standing man.

In a case like this, the blanket of snow tends to counteract
the effects of the temperature drop.  Snow is an insulator.
And given that Ryouga _is_ in a sleeping bag, there is a
credibility problem here with your ending.

didn't want to know, then ran that place as fast as he could. 

ran _from_ that place...

"RANMA SAOTOME! PREPARE TO DIE!" he cried out, rushing at the 
youth in question.

Ranma didn't even acknowledge him.

Ryoga stopped just short of contact and blinked.

Ryouga normally just attacks.  It doesn't quite work for Ryouga
not to try touching or hitting Ranma at this point.

But he was soon to find, that something else was going on.

The comma in the sentence above shouldn't be there.  Also, you
may want to shorten the sentence for greater impact:  something
like "But he was soon to find that Ranma had no choice."
Keep to active verbs and short, one-syllable words when you
want impact.

Ranma walked into Ucchan's and saw her standing there with tears 
in her eyes.

Now there's a setting problem of sorts.  If Ranma was within
walking distance of Ucchan's, why did Ryouga think he was lost in
the deep woods?  Or did Ryouga unknowingly move quite some
distance when he woke up?  The latter works, but you probably
want to make it clearer.

"Ryoga," she sobbed. "Oh Ryoga. Ryoga!"
<clip> 
"Ryoga, my poor poor Ryoga... Oh, Kami-sama, how could you do 
this to me?"

I don't understand Ukyou's reaction here.  You've given us no
background to the Ryouga-Ukyou relationship, so we're forced
to assume canon.  In canon, Ukyou might be crying, but her
words would be something like "That stupid jackass... why'd
he go and do something like that?"

And why is Ukyou complaining to God about doing this to _her_?

"They found Ryoga's body in a snow drift." Ucchan wept softly. 
"He froze to death during the night."

They found Ryouga's body the following day?  In the deep woods?
With a knee-high blanket of snow covering him?  This is the
kind of situation where the body's not found until spring.

And why is the policeman coming to Ucchan's to tell Ukyou?
She's not next of kin.  If this is years later, and Ryouga and
Ukyou are married, you need to tell us.

Ryoga blinked. "Its not true." he protested. "I'm right here. 

"It's"

"I am dead." he wept. "There was so much I wanted to say, so 
much I wanted to do."

Seems contrived and artificial.  This is the right _kind_ of
epiphany, but much too early.  No struggle to accept that he's
dead?  It would also help draw your readers in if you made this
more concrete:  "I wanted to tell Akane I love her.  I wanted
to walk through the park on a moonlit night holding her hand."

Of, if you're making a point about a Ryouga-Ukyou relationship,
make it Ukyou.

"At least you're not lost anymore."

As an ending, this doesn't quite work.  It's ironic and funny,
while you seemed to be trying for a wistful tone through most
of the story.

Plot:  not much of one, but okay as it goes.
Tone:  inconsistent
Theme: none detectable, but you could develop one
Characters:  Ranma does nothing at all.  Ryouga is recognizable,
       but not terribly interesting.  Ukyou is not recognizable.

Based on this and your last story, I'd guess that you are
particularly intrigued by Ryouga's character.  This story
situation is a _very_ good opportunity to explore Ryouga's
character, but you didn't use it.  You need to _show_ us
_WHAT_ Ryouga wanted to say and _WHAT_ Ryouga wanted to do
that he got no chance to. 

Other than that, this story suffers from the same flaw as your
last one in that you don't think your premises through.  The
blizzard, for instance, was a bad idea:  it made it less
likely that Ryouga would freeze to death, and it made finding
his body implausible.  And what's up with Ukyou?  You must
have had something in mind, but you never told us.